The field of the present invention is control mechanisms for air driven diaphragm pumps.
Pumps having double diaphragms driven by compressed air directed through an actuator valve are well known. Reference is made to U.S. Pat. Nos. 5,169,296; 4,247,264; U.S. Pat. Des. Nos. 294,946; 294,947; and 275,858, all issued to James K. Wilden, the disclosures of which are incorporated herein by reference. An actuator valve operated on a feedback control system is disclosed in U.S. Pat. No. 3,071,118 issued to James K. Wilden, the disclosure of which is also incorporated herein by reference. This feedback control system has been employed with the double diaphragm pumps illustrated in the other patents.
Such pumps include an air chamber housing having a center section and two concave discs facing outwardly from the center section. Opposing the two concave discs are pump chamber housings. The pump chamber housings are coupled with an inlet manifold and an outlet manifold through ball check valves positioned in the inlet passageways and outlet passageways from and to the inlet and outlet manifolds, respectively. Diaphragms extend outwardly to mating surfaces between the concave discs and the pump chamber housings. The diaphragms with the concave discs and with the pump chamber housings each define an air chamber and a pump chamber to either side thereof. At the centers thereof, the diaphragms are fixed to a control rod which slidably extends through the air chamber housing.
Traditionally, actuator valves associated with such pumps have included feedback control mechanisms including a valve piston and airways on the control rod attached to the diaphragms. Air pressure is alternately generated in each air chamber according to control rod location, driving the diaphragms back and forth. In turn, the pump chambers alternately expand and contract to pump material therethrough. Such pumps are capable of pumping a wide variety of materials of widely varying consistency.
Turning to the area of reciprocating power, various reciprocating devices have been known to use a constant supply of air pressure and a solenoid valve to provide an alternating flow of air for driving the reciprocating motions. Such devices may require any number of mechanisms for timing of the strokes including feedback control as well as simple set interval actuation.
The present invention is directed to an air driven double diaphragm pump employing an actuator valve which provides alternating pressure to the diaphragms independently of the stroke position of the pump. In association with reciprocal control, pistons act to limit the stroke of the double diaphragms to accomplish desired pumping characteristics.
Accordingly, it is an object of the present invention to provide an improved air driven diaphragm pump. Other and further objects and advantages will appear hereinafter.